// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_GFX_FONT_LIST_IMPL_H_
#define UI_GFX_FONT_LIST_IMPL_H_

#include <string>
#include <vector>

#include "base/memory/ref_counted.h"

namespace gfx {

class Font;

// FontListImpl is designed to provide the implementation of FontList and
// intended to be used only from FontList.  You must not use this class
// directly.
//
// FontListImpl represents a list of fonts either in the form of Font vector or
// in the form of a string representing font names, styles, and size.
//
// FontListImpl could be initialized either way without conversion to the other
// form. The conversion to the other form is done only when asked to get the
// other form.
//
// For the format of font description string, see font_list.h for details.
class FontListImpl : public base::RefCounted<FontListImpl> {
public:
    // Creates a font list from a string representing font names, styles, and
    // size.
    explicit FontListImpl(const std::string& font_description_string);

    // Creates a font list from font names, styles and size.
    FontListImpl(const std::vector<std::string>& font_names,
        int font_style,
        int font_size);

    // Creates a font list from a Font vector.
    // All fonts in this vector should have the same style and size.
    explicit FontListImpl(const std::vector<Font>& fonts);

    // Creates a font list from a Font.
    explicit FontListImpl(const Font& font);

    // Returns a new FontListImpl with the same font names but resized and the
    // given style. |size_delta| is the size in pixels to add to the current font
    // size. |font_style| specifies the new style, which is a bitmask of the
    // values: Font::BOLD, Font::ITALIC and Font::UNDERLINE.
    FontListImpl* Derive(int size_delta, int font_style) const;

    // Returns the height of this font list, which is max(ascent) + max(descent)
    // for all the fonts in the font list.
    int GetHeight() const;

    // Returns the baseline of this font list, which is max(baseline) for all the
    // fonts in the font list.
    int GetBaseline() const;

    // Returns the cap height of this font list.
    // Currently returns the cap height of the primary font.
    int GetCapHeight() const;

    // Returns the expected number of horizontal pixels needed to display the
    // specified length of characters. Call GetStringWidth() to retrieve the
    // actual number.
    int GetExpectedTextWidth(int length) const;

    // Returns the |gfx::Font::FontStyle| style flags for this font list.
    int GetFontStyle() const;

    // Returns the font size in pixels.
    int GetFontSize() const;

    // Returns the Font vector.
    const std::vector<Font>& GetFonts() const;

    // Returns the first font in the list.
    const Font& GetPrimaryFont() const;

private:
    friend class base::RefCounted<FontListImpl>;

    ~FontListImpl();

    // Extracts common font height and baseline into |common_height_| and
    // |common_baseline_|.
    void CacheCommonFontHeightAndBaseline() const;

    // Extracts font style and size into |font_style_| and |font_size_|.
    void CacheFontStyleAndSize() const;

    // A vector of Font. If FontListImpl is constructed with font description
    // string, |fonts_| is not initialized during construction. Instead, it is
    // computed lazily when user asked to get the font vector.
    mutable std::vector<Font> fonts_;

    // A string representing font names, styles, and sizes.
    // Please refer to the comments before class declaration for details on string
    // format.
    // If FontListImpl is constructed with a vector of font,
    // |font_description_string_| is not initialized during construction. Instead,
    // it is computed lazily when user asked to get the font description string.
    //
    // TODO(derat): Remove laziness so that this can be removed.
    mutable std::string font_description_string_;

    // The cached common height and baseline of the fonts in the font list.
    mutable int common_height_;
    mutable int common_baseline_;

    // Cached font style and size.
    mutable int font_style_;
    mutable int font_size_;
};

} // namespace gfx

#endif // UI_GFX_FONT_LIST_IMPL_H_
